Hydraulic planetary transmission



June l2, 1945. w. 1 POLLARD 2,378,035

HYDRAULI C PLANETARY TRANSMI S S ION Filed Jan. 14, 1943 5 Sheets-Sheet l June 12, 1945. w. L.. POLLARD Filed Jan. 14, 1943 HYDRAULIC PLANETARY TRANSMISSION lli il, limi .will mi 72s 3 Sheets-Sheet 2 `Fume 12, 1945. w. PQLLARD HYDRAULIC PLANETARY TRANSMISSION Filed Jan. 14, 1943 3 Sheets-Sheet 3 Www Patented June 12, 1945 UNITED STATES PATENT OFFICE HYDRAULIC PLANETARY TRANSMISSION Willard L. Pollard, Evanston, Ill.

Application January 14, 1943, Serial No. 472,314

Claims.

My invention relates to hydraulic planetary transmissions.

One of the objects of my invention is to provide an improved hydro-planetary transmission which will have continuous-power gear-change.

A further object is to provide such a construction which will have improved means for effecting the gear-change.

Further objects and advantages of the invention will be apparent from the description and claims. l

In the drawings, in which several embodiments of my invention are shown,

Figure 1 is an axial sectional view of the transmission;

Fig. 2 is a section substantially on the line 2 2 of Fig. 1;

Fig. 3 is a fragmentary plan view of a guide and latch for the gear shift lever;

Fig. 4 is a side elevational view of one part of a torque-transmitting rotor;

,Fig. 5 is an elevational view of another part of the torque-transmitting rotor;

Figs. 6, '7 and 8 are axial sections showing other forms of transmission;

Fig. 9 is an axial view showing another form of the invention;

Fig. 10 is a perspective view of a pedal control;

Fig. l1 is a plan view of Fig. 10; and

Fig. 12 is an axial sectional view showing a modified form of transmission. v

Referring to Figs. 1 to 5, inclusive, the construction shown therein comprises a hydraulic coupler l, a planetary transmission 2, a clutch 3 for connecting the pump rotor 4 and motor shaft 5 with the ring gear 6, a one-way anchor I for preventing reverse rotation of the ring gear 6, a clutch 8 for connecting the sun gear 9 with the turbine rotor ID, a one-way anchor II for preventing reverse rotation of the sun gear 9, manually operable means I2 for controlling the two clutches 3 and 8, and clutch instrumentalities I3, which in one position connect the ring gear 6 with the driven member of the clutch 3 and connect the gear carrier I4 with the propeller shaft I5, and in another position of the clutch instrumentalities, connect the ring gear 6 with the propeller shaft I5 and hold the gear carrier I4 against rotation.

The pump rotor 4 is secured to rotate with the motor shaft 5. The driven plate member I6 of I mitting rotor is keyed, the clutch ring 20, keyed to the shaft I'I, clutch teeth 2| and 22 on the clutch sleeve 23, and the clutch sleeve 24 to which the ring gear 6 is keyed.

For intermediate forward speed, the clutch 3 is connected and the clutch 8 is disconnected. Under these conditions, the sun gear 9 and driven clutch member 25 are held against reverse rota.- tion by the one-way anchor I I and the ring gear A 6 is connected to rotate with the pump rotor 4 the clutch 3 is connected with the intermediate and motor shaft 5 by the clutch 3. 'I'he connection from the clutch 3 is from the driving clutch member 26 through the driven clutch plateI 6, the fluid-transmitting torque-transmitting rotor I8, the intermediate shaft I'I, the clutch ring 20, the clutch sleeve 23 and the clutch sleeve 24.

For high speed gear ratio, both clutches 3 and 8 are connected so that the sun gear 9 will be driven from the turbine rotor III and the ring gear 6 will be driven from the pump rotor 4 and motor shaft 5.

For reverse, the clutch 8 is connected, the clutch 3 is disconnected, and the clutch instrumentalities are shifted to their rear positions in which the gear carrier I4 is held against reverse rotation and the ringv gear 6 is connectedwith the propeller shaft I5. The connection from the ring gear 6 to the driven shaft I5 is through the clutch sleeve 23, the front teeth 22 of which engage the clutch sleeve 24 and the rear teeth 2I of which crsigage the clutch ring 21 on the propeller shaft The gear carrier I4 is held against reverse rotation by the clutch sleeve 28, the front teeth 29 of which engage the clutch ring 30 on the gear carrier and the rear teeth 3l of which engage the teeth 32 on the fixed clutch ring 33. Under these conditions, the sun gear 9 is driven from the turbine rotor I0 through the clutch 8, the gear carrier I4 is held against reverse rotation and the ring gear 6 and propeller shaft I5 are rotated in a reverse direction at relatively low speed. The clutches 3 and 8 may be of any usual or suitable construction, each comprising a driven clutch plate I6, a s'hiftable pressure or clamping plate 34 for engaging the driven plate i5 and a plurality of levers 35, each pivoted at 36 on the driving clutch member and provided with a roller 31 for bearing on an inclined surface on the clamping plate I6. The inner ends of these levers engage an annular groove in an axially shiftable sleeve 38, which is urged toward the driven clutch plate by a coil compression spring 39. The action of this spring 39 is such as to tend to move the levers 35 in a direction to cause the clamping plate 34 to grip the driven clutch plate IB. The positions of these sleeves are controlled by axially movable non-rotatable clutch-operating rings 48. which, in turn, are controlled by the manually operable gear-change lever 4I. A thrust bearing 42 is provided between the ring 48 and the sleeve 38.

This manually operable gear-change lever is mounted for limited universal movement on a support 43 (Fig. 2) and is shlftable to and held in any one of three diierent positions corresponding to the three gear ratios, as shown at A. B and C in Figs. l, 2 and 3, Figs. 2 and 3 of which show a slotted guide plate 44 in which the gear shift lever 4I travels. The transmission from this gear shift lever 4I to the clutch-controlling rings 49 comprises a pair of rock levers 45 and 46 oscillatingly mounted on the shaft 41. One of these levers 46 controls the front clutch 3 and the other lever 45 controls the rear clutch 8. The front clutch-controlling lever 46 is prow'ded with a pin 48 which engages the gear-changing lever 4I and with another pin '49 which engages a pin 50 on the front clutch-shifting ring 40.

The transmission from the gear-changing lever 4I to the other clutch-shifting ring 40 comprises the rock lever 45 oscillatinglyA mounted on the shaft 41 and having a pin 5I fqr engaging the gear-changing lever 4I and another pin 52 for engaging a pin 53 on the clutch-shifting ring 40. It will be noted that the action of the coil compression springs 39 is such as to hold the pins 48 and I against the lever 4|.

It should be noted that the universally mounted clutch control lever can be shifted laterally sufcently to enable it to clear the pin 48 on the rock lever 46 which controls the front clutch 3.

The operation of the gear-change lever 4I will now be described. If the lever 4| is placed in the position D, both sleeves 38 will be in mldposition and both clutches 3 and 8 will be disconnected. If the lever 4I is moved to position A, it will, because of its engagement with the pin 48, cause the pin 49 to move to the right as viewed in Figs. l and 3, and consequently force the pin 58 to the v:right because of engagement of the pin 49 with the pin 50. This will move the front clutch sleeve 38 to the right against the action of the spring 39 and will release the front clutch plate I6, permitting the ring gear 6 to be held against reverse rotation by the one-way anchor 1. Furthermore, the movement, of the lever 4I te position A will enable the pin 5I to move to the left and the pin 53 to move to the right under the action of the spring 39 of the rear clutch 8 to cause the rear clutch 8 to engage to connect the sun gear with the turbine rotor I8. This will give low speed forward. The biasing action of the springs 39 on the pins 50 and 53 is indicated by the arrows E and F in Fig. 2. The biasing action of the front spring 39 will hold the lever 4I in the recess 54 in the guide plate 44 adjacent the front position A.

For intermediate gear, the lever 4I is shifted from position A to position B. In this movement, the lever 4| will press against the pin 5I to move it to the right, forcing the pin 53 to the left by engagement of the pin 52 with the pin 53. This will release the rear clutch 8 because of the left hand movement of the sleeve 38 and will enable the front clutch 3 to move to connecting position since the spring 39 of the front clutch will cause the pin 48 to follow up the movement of the clutch-controlling lever 4|. The clutch-controlling lever 4I will be held in engagement with the retaining notch 55 in the plate 44 by the action of the spring 39 of the rear clutch 8. In this position of the clutch lever 4|, the front clutch 3 will be connected and the rear clutch 8 will be disconnected, thus driving the ring gear 6 from the motor shaft 5 and allowing the sun gear 9 to fall back on the one-way anchorage II.

For high gear, the lever 4| is moved to position C. The initial lateral movement of the lever 4l moves it out of engagement with the pin 48. so that the spring 39 of the front clutch 3 will hold the front clutch 3 in connected position. The movement of the lever 4I to position C will allow the spring 39 of the rear clutch 8 to expand and place the clutch in connected position since this left hand movement of the lever 4| enables the pin 5| to move to the left allowing the pin 53 to move to the right. Under these conditions, with both clutches 3 and 8 connected, the sun gear will be connected to the turbine rotor I0 and the ring gear will be connected with the motor shaft 5. Under these circumstances, approximately twothirds of the power will be by-passed around the hydraulic part of the transmission.

Figs. 4 and 5 show somewhat in detail the construction of the duid-transmitting torque-transmitting rotor. As shown, it comprises two parts 55 and 51 secured together at their rims. One part 56 comprises a flat sheet extending between the pump rotor 4 and the turbine rotor I0, having a central hub portion 58 secured to a hub keyed to the shaft I1, arcuate portions 59 secured to the corresponding arcuate portions 68 on the other part 51 of the rotor and spoke portions 5I connecting the arcuate portions 59 with the hub portion 58. 'I'his construction enables relatively free flow of the liquid.

The other portion 51 of the rotor comprises a hub 62 secured to a hub 63 keyed to the shaft I9. The aforesaid arcuate portions 60 are secured to the arcuate portions 59 of the flat rotor portion 58 and the spoke portions 64 connect the arcuate portions with the hub portion. This construction also minimizes friction and turbulence.

The construction shown in Fig. 6 comprises a motor-driven shaft 65, a propeller shaft 66, a hydraulic coupler 81, a hydraulic torque converter 68 and a planetary gear construction 69. The coupler 61 comprises a turbine rotor 10 keyed to the motor shaft 65 and a pump rotor 1I keyed to a sleeve 12 on the ring gear 8|. The torque converter comprises a pump rotor 14 secured to rotate with the gear carrier 15 of the planetary transmission, a turbine rotor 'i6 keyed to the propeller shaft and a stato-rotor 11 held against reverse rotation by a one-way anchor 18. The gear carrier 15 is keyed to the motor shaft 65. The sun gear 19 is keyed to the propeller shaft 66.

With this construction, power supplied from the motor shaft 65 to the gear carrier 15 is divided along three paths. One path is from the gear carrier through the planet gearing to the sun gear 19. Another path is from the gear carrier 15 through the pump rotor 14, stato-rotor 11 and turbine rotor 16 to the propeller shaft 66. The third path is through the planet gearing 80. ring gear 8|, hollow shaft 12, pump rotor 1|, turbine rotor 10, motor shaft 65 and gear carrier 15, this latter path forming in effect a regenerative circuit with slip in the circuit between 'the pump rotor 1| and turbine rotor 10.

The coupler 61 and converter B8 can be so designed that when there is a high torque load on the propeller shaft, alarge proportion of the power required will be distributed through the torque converter, thus giving a relatively high torque, and so that when the torque load on the propeller shaft is relatively low, a large proportion of the power required at the propeller shaft will be distributed through the hydraulic coupler 61 and the sun gear 19.

It will also be noted that in this construction, the difference in speed between the turbine rotor 10 and pump rotor 1| of the coupler will be materially less than the difference in speed between the turbine rotor 16 and the pump rotor 14 of the hydraulic torque converter. A

The construction shown in Fig. 7 is similar to that just described, except in tlis form, the sun gear 19 is connected to rotate with the pump rotor 1| of the coupler 61 and the ring gear 8| is connected to rotate with the propeller shaft 66. In this form, the difference in speed between the tur bine rotor and pump rotor of the hydraulic coupler 61 will be materially greater than the difference in speed between the turbine rotor and pump rotor of the hydraulic torque converter 68.

The construction shown in Fig. 8 is quite similar to that slown in Fig. '1. In Fig. 8, the pump rotor 10a of the coupler is mounted on a sleeve 82 rotatable with the sun gear 19 and the turbine rotor 1|a of the couper is mounted on a sleeve 83 rotatable with the pump rotor 14 of the converter. A one-way clutch 84 is provided between the gear carrier and the pump rotor 14 which enables the gear carrier to drive the pump rotor 14 at times when the turbine rotor 1| does not develop sufficient torque to cause the pump rotor 14 to precess with respect to the gear carrier 15.

In this construction, there will be, in general, two conditions in both of which torque increase is obtained between the motor shaft 65 and the propeller shaft 66. In the rst condition, it will be assumed that the power and load are such that the torque exerted by the turbine rotor 1| is so slight as not to cause the pump rotor 14 to precess with respect to the gear carrier 15. Un-

der these conditions, the main power path from i the motor shaft 65 to the propeller shaft 66 will be through the gear carrier 15, one-way clutch 84, pump rotor 14. stato-rotor 11 and turbine rot'or 16 to the propeller shaft 66. This will give a relatively high torque increase. as only a small proportion of the `power flow is through the ring gear 8| and the coupler 61.

In the second condition, it is assumed that the load and power conditions are such that the torque exerted on, the turbine rotor 1|a by the pump rotor 10a is sufficient to cause the pump rotor 14 to precess with respect to the gear carrier 15. Under these conditions, the power flow between the motor shaft 65 and the propeller shaft B6 will be divided, part going through the coupler 61 and converter 68, and part going through the ring gear 69. This will give a rela'- tively high efficiency, as a large proportion of the power does not flow through the hydraulic part of the transmission.

When the load and power conditions are such that the torque on the stato-rotor 11 changes from -reverse to direct, the stato-rotor 11 will begni to rotate in the direction of rotation of the pump rotor 14 and the converter 68 will begin to act as a coupler.

The construction shown in Fig, 9 comprises a fluid coupler 85 which may be driven from a motor, a compound planetary transmission 86 and a twin disc clutch 81 for changing the speed ratio of the planetary transmission.

The hydro-coupler 85 comprises a pump rotor 88 which may be secured to the crankshaft of the motor, a turbine rotor 89 secured to a hub 90 which is secured to the intermediate shaft 9|, a lling opening closed by a plug 92, an oil seal 93, and a ball bearing 94 between the hub 90 and the pump rotor 88.

The planetary transmission 86 comprises a gear carrier 95 secured to rotate with the propeller shaft 96, planet gearing 91 mounted on said gear carrier, a sun gear 98 secured to the intermediate shaft 9| and meshing with the planet gearing 91, a ring gear 99 meshing vwith the planet gearing 91 and mounted on a sleeve |02 on which the clutch plate |03 is splined, planet gearing |00 mounted on the ring gear 99, a sun gear |0| meshing with the planet gearing |00 and secured to a tubular shaft |05 on which one of the clutch plates |06 is splined, a ring gear |04 meshing with the planet gearing |00, a one-way anchor |01 for preventing reverse rotation of the sun gear with respect to the ring gear, a one-way anchor |08 for preventing reverse rotation of the ring gear |04, and a ball bearing |09 between the housing ||0 and the ring gear |04.

The twin disc clutch construction 81 comprises the driving head ll secured to rotate with the pump rotor 8B, the pressure plate 2 operating between the two clutch discs |03 and |06, a handle 3 for operating the pressure plate H2, and transmission between the handle ||3 and pressure plate l2 whereby in mid-position of the operating lever or handle |13 neither clutch plate will be connected, whereby in the left-hand position of the operating lever, the front clutch plate |03 controlling the ring gear 99 will be connected and the rear clutch plate |06 will be disconnected, and in the right-hand position of the operating lever the rear clutch plate |06 secured to the sun gear |0| will be connected and the front clutch plate |03 will be disconnected.

This transmission between the lever ||3 and pressure plate l2 comprises a rockshaft ||4 to which the operating lever ||3 is secured. a short crank arm ||5 secured to this rockshaft ||4, a nonrotatable clutch shifting ring ||6 having trunnions ||1 engaged by the short rock lever ||5 and shifted back and forth by movement of the lever I3. another clutch shifting ring ||.1a rotatable with the clutch driving head Ill, a ball bearing ||8 between the two clutch shifting rings to enable rotation of the second clutch shifting ring ||1, a plurality of links ||9 each.

pivotally mounted at |21 on the clutch driving head and a plurality of links |28 pivotally connected at |29 with the three-armed rock lever |26 and pivotally connected at |30 with the pressure plate ||2 of the clutch. The above-described clutch construction is substantially standard construction and well known in this art.

The rightand left-hand members of the driving head may be secured to rotate together in any suitable manner as by means of bolts, as shown in Fig. 14 of my Patent No. 2,302,714.

With this construction for low gear, the clutch lever is placed in a neutral position in which neither clutch plate is connected. Under Athese conditions, the one-way anchorage |08 holds the ring gear |04 against reverse rotation, the oneway clutch |01 holds the sun gear |0| against reverse rotation and thus the ring gear 99 is held against reverse rotation. The turbine rotor 89 is driven from the pump rotor 08, thus driving the gun gear 98. Assuming a gear ratio of 2:1 of the ring gear and sun gear, this will give a speed ratio between the intermediate shaft 9| and propeller shaft 96 of approximately 3:1.

If it is desired to shift to intermediate gear, the clutch lever ||3 is moved rearwardly, connecting the clutch plate |06 to rotate with the pump rotor 88. Under these conditions, the oneway anchor |08 will hold the ring gear |04 against reverse rotation, and the ring gear 99 will be driven at a relatively low speed by the action of the sun gear |0|. This will increase the speed of the propeller shaft 96 since now the ring gear 99 also is rotated. With a gear ratio of approximately 2:1 between the ring gear |04 and the sun gear |0I, the overall speed ratio between the intermediate shaft 9| and propeller shaft 96 will be approximately 9:5.

If, now, it is desired to shift to high gear, or substantially direct drive, the lever ||3 is moved to the left as far as it will go, disconnecting the rear clutch plate |06 and connecting the front clutch .plate |03. This will connect the ring gear 99 to rotate wtih the pump rotor 88 and crankshaft. Under these conditions, there is substantially a direct drive between the motor andY propeller shaft 96.

It will be noted that both in intermediate speed and in direct drive a large proportion of the power is by-passed around the hydraulic part of the transmission and that in thej shift from one gear ratio to another there is continuous power flow.

It may be desirable, in shifting 'from intermediate gear, in which the sun gears |0| and 98 are supplying power, to high gear in which power is supplied by the sun gear 90 and ring gear 99, to maintain the power iiow through the sun gear |0| after the pressure plate ||2 has released the clutch plate |06 until the pressure plate ||2 is in substantially neutral position. If desired, this may be accomplished by securing a shifter ring |a integral with the splined sleeve which operates a dog clutch sleeve |30b splined on the sleeve of the driving head This dog clutch sleeve |30b is movable into and out of engagement with a dog clutch ring |30 integral with the sleeve |05 on which the sun gear |0| is mounted. A lost motion connection is provided between the flange on the splined clutch sleeve |30b and the flange on the shifter ring |30 in order that the clutch sleeve |30h will not engage the clutch ring |30c until after the pressure plate H2 has gripped the clutch disc |06. After this gripping action takes place, a slight further movement of the lever ||3 will effect the dog clutch engagement, which will positively connect the driving head with the sun gear |0I. In shifting from intermediate to high, by shifting the lever ||3 from its rearward to its forward position, the first movement of the latter will release the clutch plate |06 but will not release the dog clutch ring |30c until the lever ||3 has been moved substantially to neutral position, due to the lost motion connection between the clutch shifting ring |30a and the splined clutch sleeve |30".

This will continue the power flow through the sun gear |0| until the lever ||3 is in neutral position. A further short movement of the lever ||3 will force the pressure plate ||2 forward t0 grip the clutch plate |03 to cause power flow through the ring gear 99.

In Figs. 10 and 11` is shown a pedal construction which may be substituted for the hand lever shown in Fig. 9. This pedal construction comprises a pedal 3| secured to the rock shaft ||4 which effects the clutch control, a coil tension spring |32 connected to the pedal |3| to urge it in clockwise direction, a. coil compression spring |33 surrounding the shaft ||4 `and urging the pedal |3| to the right, as viewed in Fig. 10, a slotted plate |34 through which the pedal lever |3| extends for controlling the movement of the pedal, and bearing brackets |35 for the rock shaft H4. The rock lever ||5 may be mounted on the rock shaft H4. The pedal |3| has three positions determined by the formation of the slot |36 in the plate |34. In the right-hand position, the pedal lever is in the right-hand notch |31, the tension spring |32 holding it in this position. In this position, the rear clutch plate |06 may be connected for intermediate speed. For low speed, the pedal is depressed to bring the front edge |38 of the lever against the sloping shoulder |39 on the slot which will edge the lever upwardly as viewed in Fig. 1l to bring the rear edge of the lever in front of the shoulder |40 of the slot, whereupon. the coil compression spring |33 will snap the lever over to the position as shown in Fig. 11. In this position, the transmission will be in low gear, neither clutch plate being connected. For high gear, the pedal |3| is again depressd to bring the front edge of the lever against the sloping shoulder |4| of the slot. This will give the lever |3| another shift upwardly, as viewed in Fig. 11, bringing the rear edge of the lever in front of the shoulder |42 of the slot, whereupon the coil compression spring |33 will snap the lever upwardly, as viewed in Fig. 11, causing the lever to be held securely in its forward position. This will give the lhigh gear ratio, the clutch plate |03 being connected. To operate the lever to/cause it to move rearwardly, the foot is brought into engagement with the finger |43 on the pedal to press the pedal to the left, as viewed in Fig. 10, to bring the corner of the lever against the sloping shoulder |4| of the slot, forcing the lever to,the1.right.to bring the lever |3| below the shoulder |44 in the slot, as viewed in Fig. 11. The coil tension Vspring |32 will then jerk the lever to the full-line position shown in Fig. l1. To go into high gear, the foot is again brought into engagement with the finger |43 on the foot pedal to move it downwardly, as

viewed in Fig. 11, to bring the corner of the lever against the sloping shoulder |39 of the slot. This will brin'gthe lever below the shoulder |45 in the slot and the coil tension spring |32 will again snap the lever to the right, as viewed in Fig. l1, to place the transmission in high gear, the clutch plate |06 being connected. f

The construction shown in Fig. 12 may be in general similar to that shown in Fig. 9, except that a somewhat different form of planetary gearing is used and a power device is provided forl effecting the gear change.

Referring, first, to the planetary gearing, the gez.: parts 95, 91, 98, 99, |00, and |04 may be substantially the same as shown in Fig. 9. In this form, however, the gear carrier |46 which carries the planet gearing |00 is connected to the sleeve of the rear clutch disc |06, and the ring gear |04 is oating except as it is controlled by the brake band |4'l. Brake bands |41 and |48 are substituted for the one-way anchors |08 and |01 of Fig. 9.

In this form, for low gear, both clutch plates |03 and |06 are disconnected, and both brakes |41 and |48 may be applied as shown in Fig. 12. With the ring gear 99 thus held and the sun gear 98 driven from the turbine rotor, the speed ratio of the intermediate shaft to propeller shaft will be approximately 3:1. For intermediate speed, the brake controlling rod |49 is moved to the right to disconnect the rear brake |48, the front brake still remaining connected. This movement of the rock shaft ||4A to effect the brake operation also connects the front clutch plate |03, leaving the rear clutch plate |06 disconnected. Under these conditions, therefore, the sun gear |0| rotates with the pump rotor 88, the ring gear |04 is held against rotation and the rear ring gear 99 is freed for rotation. Under these conditions, the speed ratio between the intermediate shaft and the propeller shaft will be approximately 9:5. For high gear, the rock shaft ||4 is operated to disconnect the front clutch plate |03, connect the rear clutch plate, and move the control rod |49 to the left to disconnect both brakes. Underthese conditions, the combination of gear carrier |05 and ring gear 99 is connected to rotate with the pump rotor 88, and the sun gear 98 is connected to rotate with the turbine rotor. This gives substantially direct drive.

The rock shaft ||4 which controls the clutches and brakes may have a pin |50 on the rock arm |5| for engagement with the short rock arm ||5 which controls the clutch shifting rings ||6 and The power mechanism for controlling this rock shaft comprises the rock arm |5| secured to the rock shaft ||4 and two fiuld actuators |52 for controlling this rock arm. Each fiuid actuator |52 may comprise a casing |53` in which a fiexible cl aphragm |54 is mounted, one side of the diaphragm being subjected to atmospheric pressure and the other side being connectible with the manifold or the like. The diaphragms of the two actuators may be connected with a common operating rod |55 having a pair of op erating pins |56 between which ythe actuating lever |5| for the rock shaft ||4 extends.

A centralizing spring |51 may be provided for bringing the rock shaft H4 to neutral position when neither of the diaphragms |54 is subjected to the vacuum in the manifold. This centralizing spring may be of any usual or suitable construction, that shown comprising a coil torsion spring between the ends |58 of which the rock lever |5| is embraced, and a pair of stop pins |59 engageable by the spring arms to vlimit their movement but not engageable by the rock arm |5| in its movement. With this construction, it will be seen that when a vacuum is created in the right-hand actuator, the actuating rod will be moved to the right, assuming that the left-hand actuator is not subjected to vacuum and that if the left-hand actuator is subjected to vacuum and the right-hand actuator is not subjected to vacuum, the actuating rod will move to the left.

For vehicle propulsion, for example in tractors, the shaft 96 may be coupled to a low and reverse gear box, giving an overall range o f'six forward speeds and three reverse speeds.

Further modifications will be apparent to those skilled in the art and it is desired, therefore, that the invention be limited only by the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A hydro-planetary transmission comprising a drive shaft, a pump rotor driven therefrom, a turbine rotor driven from said pump rotor, a driven shaft, a first planetary gearing comprising a -first gear carrier mounted on said driven sha'ft, a first planet gearing mounted on said gear carrier, a iirst sun gear and a first ring gear both meshing with said planet gearing, a shaft on which said sun gear and turbine rotor are mounted, a second planetary gearing comprising a second gear carrier secured to rotate with said first ring gear, a second planet gearing mounted on said second gear carrier, a second ring gear and a second sun gear both meshing with said second planet gear gearing, a first clutch means for placing said second sun gear into and out of positive driven relation with respect to said drive shaft, a second clutch means for placing the ring gear of said second planetary gearing into and out of positive driven relation Withrespect to said drive shaft, and means for holding said second ring gear against reverse rotation with respect to the rotation of said drive shaft.

2. A hydro-planetary transmission comprising a, drive shaft, a pump rotor driven therefrom, a turbine rotor driven from said pump rotor, a driven shaft, a first planetary gearing comprising a first gear carrier mounted on said driven shaft, a first planet gearing mounted on said gear carrier, a rst sun gear and a first ring gear both meshing with said planet gearing, a shaft on which said sun gear and turbine rotor are mounted, a second planetary gearing comprising a second gear carrier secured to rotate with said first ring gear, a second planet gearing mounted on said second gear carrier, a second ring gear and a second sun gear both meshing with said second planet gearing, a first clutch means for placing said second sun gear into and out of positive driven relation with respect to said drive shaft, a second clutch means for placing the ring gear of` said second planetary gearing into and' out of positive driven relation with respect to said drive shaft, means for holding said second ring gear against reverse rotation with respect to the rotation of said drive shaft, and common reciprocable means for actuating both said first clutch means and said second clutch means.

3. A hydro-planetary transmission comprising a drive shaft, a pump rotor driven therefrom, a turbine rotor driven from said pump rotor, a driven shaft, a first planetary gearing comprising a first gear carrier mounted on said driven shaft, a first planet gearing mounted on said gear carrier, a first sun gear and a first ring gear both meshing with said planet gearing, a shaft on which said sun gear and turbine rotor are mounted, a second planetary gearing comprising a second gear carrier secured to rotate with said rst ring gear, a second planet gearing mounted on said second gear carrier, a second ring gear and a second s un gear both meshing with said second planet gearing, a first clutch means for placing said second sun gear into and out of positive driven relation with respect to said drive shaft, a second clutch means for placing the ringr gear of said second .planetary gearing into and out of positive driven relation with respect to said drive shaft, means for holding said second ring gear against reverse rotation with respect to the rotation of said drive shaft, and common reciprocable means for actuating both said first clutch means and said second clutch means, comprising means which, at one end of the reciprocable movement, connect the first clutch means and disconnect the second clutch means and which at the other end of the reciprocable movement, connect the second clutch means and disconnnect the iirst clutch means.

4. A hydro-planetary transmission comprising a drive shaft, a pump rotor driven therefrom, a turbine rotor driven from said pump rotor, a driven shaft, a first planetary gearing comprising a first gear carrier mounted on said driven shaft, a first planet gearing mounted on said gear carrier, a first sun gear and a iirst, ring gear both meshing with said planet gearing, a Shaft on which said sun gear and turbine rotor are mounted, a second planetary gearing comprising a second gear carrier secured to rotate with said iirst ring gear, a second planet gearing mounted on said second gear carrier, a second ring gear and a second sun gear both meshing with said second planet gearing, a rst clutch means for placing said second sun gear into and out of positive driven relation with respect to said drive shaft, a second clutch means for placing the ring gear of said second planetary gearing into and out of positive driven relation with respect to said drive shaft, means for holding said. second ring gear against reverse rotation with respect to the rotation of said drive shaft, and common reciprocable means for actuating both said first clutch means and said second clutch means, comprising means which, at one end of the recipricable movement, connect the first clutch means and disconnect the second clutch means and which, at the other end of the reoiprocable movement, connect the second clutch means and disconnect the first clutch means and, in an intermediate position, disconnect both clutch means from positive driven relation.

5. A hydro-planetary transmission comprising a drive'shaft, a pump rotor driven therefrom, a turbine rotor driven from said pump rotor, a driven shaft, a first planetary gearing comprising a first gear carrier mounted on said driven shaft, a first planet gearing mounted on said gear carrier, a first sun gear and a first ring gear both meshing with said planet gearing, a shaft on which said sun gear and turbine rotor are mounted, a second planetary gearing comprising a second gear carrier secured to rotate with said first ring gear, a second planet gearing mounted on said second gear carrier, a second ring gear and a second sun gear both meshing with said second planet gearing, a first clutch means for placing said second sun gear into and out of positive driven relation with respect to said drive shaft, a second clutch means for placing said second ring gear into and out of driven relation with respect to said drive shaft, and'means'for holding said ring gear against reverse rotation with respect to the rotation of said drive shaft.

W'IILARD L. POLLARD. 

